h | $2^{-8} $ | $2^{-9} $ | $2^{-10} $ |
$Cond(\mathsf{A})$ | $ 2.329917 \times 10^{6}$ | $ 9.320396 \times 10^{6}$ | $ 3.728232 \times 10^{7}$ |
We develop a fast Hermite finite element method for a one-dimensional space-fractional diffusion equation, by proving that the stiffness matrix of the method can be expressed as a Toeplitz block matrix. Then a block circulant preconditioner is presented. Numerical results are presented to show the utility of the fast method.
Citation: |
Table 1.
The condition number of stiffness matrix
h | $2^{-8} $ | $2^{-9} $ | $2^{-10} $ |
$Cond(\mathsf{A})$ | $ 2.329917 \times 10^{6}$ | $ 9.320396 \times 10^{6}$ | $ 3.728232 \times 10^{7}$ |
Table 2.
The
$\beta$ | h | DOF | $ \|u_h - u \|_{L^2}$ | order | $ \|u_h - u \|_{H^{1-\frac{\beta}{2}}}$ | order |
0.5 | $2^{-3} $ | 16 | $ 4.872892 \times 10^{-4}$ | $ 2.512934 \times 10^{-3}$ | ||
$2^{-4} $ | 32 | $ 3.573631 \times 10^{-5}$ | 3.7693 | $ 2.576521 \times 10^{-4}$ | 3.2858 | |
$2^{-5} $ | 64 | $ 2.236217 \times 10^{-6}$ | 3.9982 | $ 2.481970 \times 10^{-5}$ | 3.3758 | |
$2^{-6} $ | 128 | $ 1.342295 \times 10^{-7}$ | 4.0582 | $ 2.249708 \times 10^{-6}$ | 3.4636 | |
$2^{-7} $ | 256 | $ 7.909661 \times 10^{-9}$ | 4.0849 | $ 2.033970 \times 10^{-7}$ | 3.4673 | |
0.1 | $2^{-3} $ | 16 | $ 7.851432 \times 10^{-4}$ | $ 8.011606 \times 10^{-3}$ | ||
$2^{-4} $ | 32 | $ 6.192597 \times 10^{-5}$ | 3.6643 | $ 1.304843 \times 10^{-3}$ | 2.6352 | |
$2^{-5} $ | 64 | $ 4.208159 \times 10^{-6}$ | 3.8792 | $ 1.805192 \times 10^{-4}$ | 2.8536 | |
$2^{-6} $ | 128 | $ 2.713900 \times 10^{-7}$ | 3.9547 | $ 2.295487 \times 10^{-5}$ | 2.9752 | |
$2^{-7} $ | 256 | $ 1.794745 \times 10^{-8}$ | 3.9185 | $ 2.808095 \times 10^{-6}$ | 3.0311 | |
0.9 | $2^{-3} $ | 16 | $ 3.622149 \times 10^{-4}$ | $ 4.846137 \times 10^{-4}$ | ||
$2^{-4} $ | 32 | $ 2.767086 \times 10^{-5}$ | 3.7104 | $ 4.110739 \times 10^{-5}$ | 3.5593 | |
$2^{-5} $ | 64 | $ 1.826287 \times 10^{-6}$ | 3.9213 | $ 3.012015 \times 10^{-6}$ | 3.7705 | |
$2^{-6} $ | 128 | $ 1.180438 \times 10^{-7}$ | 3.9515 | $ 2.132241 \times 10^{-7}$ | 3.8202 | |
$2^{-7} $ | 256 | $ 7.376961 \times 10^{-9}$ | 4.0001 | $ 1.415327 \times 10^{-8}$ | 3.9131 |
Table 3.
Performance of Gauss, CGS methods with
Gauss | CGS | |||
h | CPU(s) | Itr. # | CPU(s) | Itr. # |
$2^{-6}$ | 0.0916 | 0.2103 | 137 | |
$2^{-7}$ | 0.4865 | 1.5369 | 272 | |
$2^{-8}$ | 3.5858 | 9.8734 | 415 | |
$2^{-9}$ | 24.4774 | 62.7682 | 665 | |
$2^{-10}$ | 186.9874 | 391.5595 | 899 | |
$2^{-11}$ | 1485.1450 | 2731.0751 | 1676 | |
$2^{-12}$ | out of memory | out of memory |
Table 4.
Performance of FCGS, SFCGS and PFCGS methods with
FCGS | SFCGS | CFCGS | ||||
h | CPU(s) | Itr. # | CPU(s) | Itr. # | CPU(s) | Itr. # |
$2^{-6}$ | 0.0832 | 137 | 0.0305 | 7 | 0.0341 | 9 |
$2^{-7}$ | 0.1809 | 272 | 0.0358 | 7 | 0.0419 | 10 |
$2^{-8}$ | 0.2890 | 415 | 0.0503 | 7 | 0.0445 | 11 |
$2^{-9}$ | 0.9907 | 665 | 0.0680 | 8 | 0.0653 | 12 |
$2^{-10}$ | 2.4525 | 899 | 0.0932 | 8 | 0.1046 | 14 |
$2^{-11}$ | 16.0752 | 1676 | 0.1536 | 9 | 0.2422 | 16 |
$2^{-12}$ | 26.4751 | 6421 | 0.1914 | 9 | 0.5955 | 19 |
$2^{-13}$ | N/A | $>$ 30,000 | 0.6319 | 10 | 1.4107 | 22 |
T. Basu
and H. Wang
, A fast second-order finite difference method for space-fractional diffusion equations, Int. J. Numer. Anal. Mod., 9 (2012)
, 658-666.
![]() ![]() |
|
D. Benson
, S. W. Wheatcraft
and M. M. Meerschaert
, The fractional-order governing equation of Lévy motion, Water Resour. Res., 36 (2000)
, 1413-1423.
doi: 10.1029/2000WR900032.![]() ![]() |
|
W. Bu
, Y. Tang
and J. Yang
, Galerkin finite element method for two-dimensional Riesz space fractional diffusion equations, J. Comput. Phys., 276 (2014)
, 26-38.
doi: 10.1016/j.jcp.2014.07.023.![]() ![]() ![]() |
|
R. H. Chan
and M. K. Ng
, Conjugate gradient methods for Toeplitz systems, SIAM Review, 38 (1996)
, 427-482.
doi: 10.1137/S0036144594276474.![]() ![]() ![]() |
|
R. H. Chan
, Circulant preconditioners for Hermitian Toeplitz systems, SIAM Journal on Matrix Analysis and Applications, 10 (1989)
, 542-550.
doi: 10.1137/0610039.![]() ![]() ![]() |
|
R. H. Chan
and X. Q. Jin
, A family of block preconditioners for block systems, SIAM journal on scientific and statistical computing, 13 (1992)
, 1218-1235.
doi: 10.1137/0913070.![]() ![]() ![]() |
|
P. J. Davis,
Circulant Matrices, Wiley-Intersciences, New York, 1979.
![]() ![]() |
|
W. Deng
, Finite element method for the space and time fractional Fokker-Planck equation, SIAM Journal on Numerical Analysis, 47 (2008)
, 204-226.
doi: 10.1137/080714130.![]() ![]() ![]() |
|
K. Diethelm
and A. D. Freed
, An efficient algorithm for the evaluation of convolution integrals, Computers and Mathematics with Applications, 51 (2006)
, 204-226.
doi: 10.1016/j.camwa.2005.07.010.![]() ![]() ![]() |
|
N. Du
and H. Wang
, A fast finite element method for space-fractional dispersion equations on bounded domains in $\mathbb{R}^2$, SIAM J. Sci. Comput., 37 (2015)
, A1614-A1635.
doi: 10.1137/15M1007458.![]() ![]() ![]() |
|
V. J. Ervin
and J. P. Roop
, Variational formulation for the stationary fractional advection dispersion equation, Numer. Methods for Partial Differential Equations, 22 (2005)
, 558-576.
doi: 10.1002/num.20112.![]() ![]() ![]() |
|
V. J. Ervin
and J. P. Roop
, Variational Solution of Fractional Advection Dispersion Equations on Bounded Domains in $R^{d}$, Numer. Methods for Partial Differential Equations, 23 (2007)
, 256-281.
doi: 10.1002/num.20169.![]() ![]() ![]() |
|
R. M. Gray
, Toeplitz and circulant matrices: A review, Communications and Information Theory, 2 (2016)
, 155-239.
doi: 10.1561/0100000006.![]() ![]() |
|
J. Jia
and H. Wang
, A preconditioned fast finite volume scheme for a fractional differential equation discretized on a locally refined composite mesh, J. Comput. Phys., 299 (2015)
, 842-862.
doi: 10.1016/j.jcp.2015.06.028.![]() ![]() ![]() |
|
Y. Jiang
and X. Xu
, Multigrid methods for space fractional partial differential equations, J. Comput. Phys., 302 (2015)
, 374-392.
doi: 10.1016/j.jcp.2015.08.052.![]() ![]() ![]() |
|
S. L. Lei
and H. W. Sun
, A circulant preconditioner for fractional diffusion equations, J. Comput. Phys., 242 (2013)
, 715-725.
doi: 10.1016/j.jcp.2013.02.025.![]() ![]() ![]() |
|
C. Li
, Z. Zhao
and Y. Q. Chen
, Numerical approximation of nonlinear fractional differential equations with subdiffusion and superdiffusion, Computers and Mathematics with Applications, 62 (2011)
, 855-875.
doi: 10.1016/j.camwa.2011.02.045.![]() ![]() ![]() |
|
X. Li
and C. Xu
, The existence and uniqueness of the weak solution of the space-time fractional diffusion equation and a spectral method approximation, Commun. Comput. Phys., 8 (2010)
, 1016-1051.
doi: 10.4208/cicp.020709.221209a.![]() ![]() ![]() |
|
F. R. Lin
, S. W. Yang
and X. Q. Jin
, Preconditioned iterative methods for fractional diffusion equation, J. Comput. Phys., 256 (2014)
, 109-117.
doi: 10.1016/j.jcp.2013.07.040.![]() ![]() ![]() |
|
Y. Lin
and C. Xu
, Finite difference/spectral approximations for the time-fractional diffusion equation, J. Comput. Phys., 225 (2007)
, 1533-1552.
doi: 10.1016/j.jcp.2007.02.001.![]() ![]() ![]() |
|
F. Liu
, V. Anh
and I. Turner
, Numerical solution of the space fractional Fokker-Planck equation, J. Comput. Appl. Math., 166 (2014)
, 209-219.
doi: 10.1016/j.cam.2003.09.028.![]() ![]() ![]() |
|
C.~W. Lv
and C. Xu
, Improved error estimates of a finite difference/spectral method for time-fractional diffusion equations, Int. J. Numer. Anal. Mod., 12 (2015)
, 384-400.
![]() ![]() |
|
M. M. Meerschaert
, H. P. Scheffler
and C. Tadjeran
, Finite difference methods for two-dimensional fractional dispersion equation, J. Comput. Phys., 211 (2006)
, 249-261.
doi: 10.1016/j.jcp.2005.05.017.![]() ![]() ![]() |
|
M. M. Meerschaert
and C. Tadjeran
, Finite difference approximations for fractional advection-dispersion flow equations, J. Comput. Appl. Math., 172 (2004)
, 65-77.
doi: 10.1016/j.cam.2004.01.033.![]() ![]() ![]() |
|
R. Metzler
and J. Klafter
, The random walk's guide to anomalous diffusion: A fractional dynamics approach, Phys. Rep., 339 (2000)
, 1-77.
doi: 10.1016/S0370-1573(00)00070-3.![]() ![]() ![]() |
|
H. K. Pang
and H. W. Sun
, Multigrid method for fractional diffusion equations, J. Comput. Phys., 231 (2012)
, 693-703.
doi: 10.1016/j.jcp.2011.10.005.![]() ![]() ![]() |
|
I. Podlubny,
Fractional Differential Equations, Academic Press, New York, 1999.
![]() ![]() |
|
Y. Saad,
Iterative Methods for Sparse Linear Systems, 2nd ed. , SIAM, Rhode Island, 2003.
doi: 10.1137/1. 9780898718003.![]() ![]() ![]() |
|
H. G. Sun
, W. Chen
and Y. Q. Chen
, Fractional differential models for anomalous diffusion, Physica A: Statistical Mechanics and its Applications, 389 (2010)
, 2719-2724.
doi: 10.1016/j.physa.2010.02.030.![]() ![]() |
|
H. Tian
, H. Wang
and W. Q. Wang
, An efficient collocation method for a non-local diffusion model, Int. J. Numer. Anal. Mod., 10 (2013)
, 815-825.
![]() ![]() |
|
P. Vabishchevich
, Numerical solution of nonstationary problems for a convection and a space-fractional diffusion equation, Int. J. Numer. Anal. Mod., 13 (2016)
, 296-309.
![]() ![]() |
|
H. Wang
and D. P. Yang
, Wellposedness of variable-coefficient conservative fractional elliptic differential equations, SIAM Journal on Numerical Analysis, 51 (2013)
, 1088-1107.
doi: 10.1137/120892295.![]() ![]() ![]() |
|
H. Wang
, D. P. Yang
and S. F. Zhu
, Accuracy of finite element methods for boundary-value problems of steady-state fractional diffusion equations, Journal of Scientific Computing, 70 (2017)
, 429-449.
doi: 10.1007/s10915-016-0196-7.![]() ![]() ![]() |
|
H. Wang
and X. H. Zhang
, A high-accuracy preserving spectral Galerkin method for the Dirichlet boundary-value problem of variable-coefficient conservative fractional diffusion equations, J. Comput. Phys., 281 (2015)
, 67-81.
doi: 10.1016/j.jcp.2014.10.018.![]() ![]() ![]() |
|
H. Wang
and T. Basu
, A fast finite difference method for two-dimensional space-fractional diffusion equations, SIAM J. Sci. Comput., 34 (2012)
, A2444-A2458.
doi: 10.1137/12086491X.![]() ![]() ![]() |
|
H. Wang
and N. Du
, A superfast-preconditioned iterative method for steady-state space-fractional diffusion equations, J. Comput. Phys., 240 (2013)
, 49-57.
doi: 10.1016/j.jcp.2012.07.045.![]() ![]() ![]() |
|
H. Wang
, K. Wang
and T. Sircar
, A direct $O(N\log^2 N)$ finite difference method for fractional diffusion equations, J. Comput. Phys., 229 (2010)
, 8095-8104.
doi: 10.1016/j.jcp.2010.07.011.![]() ![]() ![]() |
|
L. L. Wei
, Y. N. He
and Y. Zhang
, Numerical analysis of the fractional seventh-order KdV equation using an implicit fully discrete local discontinuous Galerkin method, Int. J. Numer. Anal. Mod., 10 (2013)
, 430-444.
![]() ![]() |